Oem bolts are M14 x 1.5 and 27mm long i think. ( not sure ) obviously you need bolts at least 5mm longer.
what you need to check is the seating, cant remember if you have now got aftermarket wheels on but most aftermarket wheels have a different seat, one bolt type is a radius seat and the other has a 60degree taper, cant remember which one is the OEM fitting either.
sorry not much help it,s been a while since i was playing with wheels.